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What does SQL clause “GROUP BY 1” mean?
...the first column regardless of what it's called. You can do the same with ORDER BY.
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Merge and interleave two arrays in Ruby
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This won't give a result array in the order Chris asked for, but if the order of the resulting array doesn't matter, you can just use a |= b. If you don't want to mutate a, you can write a | b and assign the result to a variable.
See the set union documentation ...
Can I set up HTML/Email Templates with ASP.NET?
...fit of this approach is consistency. For example, you could show a user an order summary and include exactly the same thing in the confirmation email by reusing the same control.
– Mun
Mar 26 '09 at 21:19
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Which method performs better: .Any() vs .Count() > 0?
...etter than Count() > 0 - I've had situation in which Count is faster by order of magnitude on SQL Server (EntityFramework 4).
Here is query with Any that thew timeout exception (on ~200.000 records):
con = db.Contacts.
Where(a => a.CompanyId == companyId && a.ContactStatusId <...
Remove duplicate rows in MySQL
...owing columns:
employee (id, first_name, last_name, start_date, ssn)
In order to delete the rows with a duplicate ssn column, and keeping only the first entry found, the following process can be followed:
-- create a new tmp_eployee table
CREATE TABLE tmp_employee LIKE employee;
-- add a unique...
The type must be a reference type in order to use it as parameter 'T' in the generic type or method
...koverflow.com%2fquestions%2f6451120%2fthe-type-must-be-a-reference-type-in-order-to-use-it-as-parameter-t-in-the-gen%23new-answer', 'question_page');
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Using helpers in model: how do I include helper dependencies?
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To access helpers from your own controllers, just use:
OrdersController.helpers.order_number(@order)
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How do I delete a fixed number of rows with sorting in PostgreSQL?
...DELETE FROM logtable
WHERE ctid IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly, a row's ctid will change if it is...
Condition within JOIN or WHERE
...sider these two queries:
SELECT *
FROM dbo.Customers AS CUS
LEFT JOIN dbo.Orders AS ORD
ON CUS.CustomerID = ORD.CustomerID
WHERE ORD.OrderDate >'20090515'
SELECT *
FROM dbo.Customers AS CUS
LEFT JOIN dbo.Orders AS ORD
ON CUS.CustomerID = ORD.CustomerID
AND ORD.OrderDate >'20090515'
The f...
What are good examples of genetic algorithms/genetic programming solutions? [closed]
...nute-by-minute price data of the S&P500 futures, as well as a specific order (buy or sell) and stop-loss and stop-profit amounts. Each string (or "gene") had its profit performance evaluated by a run through 3 years of historical data; whenever the specified "shape" matched the historical data,...